I know this has come up before, but the postings I read said there was a problem with !!! That was in 2010. I have been using a Uno for nearly a year without problems and now I got a mega 2560 and tried to upload the blink program. when it didn't stop unloading, I held the shift down and it gave me this message:

avrdude: usbdev_open(): did not find any USB device "usb"

My compiler settings are to mega 2560 and to port COM4. I'm on system MS 7 and I've reinstalled "the latest" arduino driver I can find... which is in the version 1.0.2 folder.

Assuming the !!! glitch was fixed long ago, can anyone tell me what the problem might be? As I said, I've compiled and uploaded to my Uno from this machine without problems. The Mega is the only new aspect.